Axial compressors are well known as such and are used in turbomachines, inter alia.
These low or high-pressure compressors comprise several stages of rotary vanes, also called rotor vanes, that are separated by rectifier stages which aim to reposition the velocity vector of the fluid leaving the preceding stage before sending it towards the following stage.
The rectifier stages are essentially made of fixed vanes, also called stator vanes, connecting an outer collar to an inner collar, both concentric and defining the air flow zone or aerodynamic vein.
The stages of rotor vanes are attached to a drum. A compressor drum is generally a hollow body that is symmetrical in revolution relative to its rotation axis, which corresponds to the axis of the turbomachine. The general shape of the hollow body is oval or cone-shaped depending on the shape of the flow.
Nowadays, the drum and the rotor vanes are generally made of a titanium alloy (TA6V) and the drum comprises circumferential recesses in which the feet of the vanes are fastened by a system of bolts. One such construction is illustrated in FIG. 1 of document EP 1 111 246 B1.
Traditional architectures with recesses do however have several drawbacks that can be listed as follows:                to prevent the opening of the recesses and thereby guarantee the resistance of the vanes and the stability of the feet within the recesses, the latter must be part of massive zones of the drums;        the feet of the vanes that are housed in these recesses are also massive (40 to 50% of the mass of the vane); this results in a substantial centrifugal mass causing even more substantial stresses in the drum;        the presence of recesses causes concentrations of stresses on the edge of the insertion notches. As a result, a traditional design with recesses takes on a substantial amount of material, of which only a relatively reduced portion is “useful” for the mechanical strength;        the feet of the vanes have some positioning latitude within the recesses creating in particular rocking phenomena, which consume axial and radial clearance.        
Document GB 1,163,752 presents an alternative to the fastening system with recesses in the rotor of an axial flow machine. The vane comprises a blade provided with a threaded member that engages in the rotor hub in order to allow the vane to be fastened to the hub.